Sure, and Polaris is never visible from Australia etc. But, it’s a much weaker argument to say these constellations limit observations by less than 10%.
The reality is there is real impact, but no where near as bad as many generally portrayed. Imagine some senator canceling funding for new ground based telescopes because they heard these satellites would render them useless.
I have heard astronomers estimating it at up to 30% of the observing time for existing optical telescopes. Note that this is the instrument class that has t to 20 times as many proposals as they can actually observe.
The reality is there is real impact, but no where near as bad as many generally portrayed. Imagine some senator canceling funding for new ground based telescopes because they heard these satellites would render them useless.